Field of the Invention
This invention relates generally to hydrogen production and, more particularly, to hydrogen production via sorbent enhanced reforming with atmospheric calcination.
Discussion of Related Art
Sorbent Enhanced Reforming (SER) is an emerging processing technology for hydrogen production with integrated CO2 capture.
Such processing typically employs Le Chatelier's principle to assist in producing high purity hydrogen. Essentially, such processing utilizes a sorbent material to adsorb carbon dioxide produced during the reforming reaction, causing the reaction to produce more carbon dioxide which is subsequently removed. The removal of the carbon dioxide preferentially shifts the thermodynamic equilibrium to a high purity hydrogen equilibrium.
A secondary benefit of SER processing is that nearly all of the carbon dioxide is retained by or in the sorbent material. To desirably enable re-use of the sorbent material, the captured carbon dioxide must subsequently be liberated from the sorbent material. The regeneration of the sorbent material is typically performed in a component known as a calciner.
There are two typical types of calcination processing: direct and indirect firing. Direct firing calcination utilizes hot gas, such as from combustion or an electrical heating processes, and mixes such hot gas directly with the sorbent material. Such direct firing calcination processing typically simplifies the solids handling approach, and reduces the calcination temperature that is required by decreasing the partial pressure of the carbon dioxide. Indirect firing calcination utilizes heat such as provided from an outside source which physically separated from the sorbent material. Such indirect firing calcination processing typically complicates the heat transfer process and increases the required calcination temperature, but provides a nearly pure carbon dioxide stream such as may be found useful for carbon capture and sequestration or co-production needs.
In the past, the calcination processing has commonly been performed at a pressure within 5% of the reactor system pressure which typically ranges from 30-363 psia.